/*
* @(#)DESCrypt.java
* Created: 11-Jul-2005
* Version: 1-1-alpha3
* Copyright (c) 2005-2006, University of Manchester All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer. Redistributions in binary
* form must reproduce the above copyright notice, this list of conditions and
* the following disclaimer in the documentation and/or other materials
* provided with the distribution. Neither the name of the University of
* Manchester nor the names of its contributors may be used to endorse or
* promote products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package memetic.crypto;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.ShortBufferException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import net.sf.fmj.utility.LoggerSingleton;
/**
* Encrypts and Decrypts using the DES Algorithm
*
* @author Andrew G D Rowley
* @version 1-1-alpha3
*/
public class DESCrypt implements Crypt {
private static final Logger logger = LoggerSingleton.logger;
/**
* The DES encryption type
*/
public static final String TYPE = "DES";
// An object for decrypting data
private Cipher decrypter = null;
// An object for encrypting data
private Cipher encrypter = null;
/**
* Creates a new DESCrypt
*
* @param password
* The password to crypt with
*/
public DESCrypt(String password) {
try {
// Generate the key by taking the MD5 of the password
MessageDigest md5 = MessageDigest.getInstance("MD5");
byte[] md5Key = md5.digest(password.getBytes("UTF-8"));
// Generate the key by compressing 8 bytes to 7
byte[] inKey = new byte[8];
inKey[0] = md5Key[0];
inKey[1] = (byte) (((md5Key[0] & 0xFF) << 7) |
((md5Key[1] & 0xFF) >> 1) & 0xFF);
inKey[2] = (byte) (((md5Key[1] & 0xFF) << 6) |
((md5Key[2] & 0xFF) >> 2) & 0xFF);
inKey[3] = (byte) (((md5Key[2] & 0xFF) << 5) |
((md5Key[3] & 0xFF) >> 3) & 0xFF);
inKey[4] = (byte) (((md5Key[3] & 0xFF) << 4) |
((md5Key[4] & 0xFF) >> 4) & 0xFF);
inKey[5] = (byte) (((md5Key[4] & 0xFF) << 3) |
((md5Key[5] & 0xFF) >> 5) & 0xFF);
inKey[6] = (byte) (((md5Key[5] & 0xFF) << 2) |
((md5Key[6] & 0xFF) >> 6) & 0xFF);
inKey[7] = (byte) (((md5Key[6] & 0xFF) << 1) & 0xFF);
// Add DES Key Padding
for (int i = 0; i < 8; ++i) {
int k = inKey[i] & 0xfe;
int j = k;
j ^= j >> 4;
j ^= j >> 2;
j ^= j >> 1;
j = (j & 1) ^ 1;
inKey[i] = (byte) ((k | j) & 0xFF);
}
SecretKeySpec secretKey = new SecretKeySpec(inKey, "DES");
decrypter = Cipher.getInstance("DES/CBC/NoPadding");
encrypter = Cipher.getInstance("DES/CBC/NoPadding");
// IV is all 0s for RTP DES
IvParameterSpec iv = new IvParameterSpec(new byte[] { 0, 0, 0, 0,
0, 0, 0, 0 });
decrypter.init(Cipher.DECRYPT_MODE, secretKey, iv);
encrypter.init(Cipher.ENCRYPT_MODE, secretKey, iv);
} catch (Exception e) {
logger.log(Level.WARNING, "" + e, e);
}
}
/**
* @throws BadPaddingException
* @throws IllegalBlockSizeException
* @throws ShortBufferException
* @throws InvalidAlgorithmParameterException
* @throws InvalidKeyException
* @see memetic.crypto.Crypt#encrypt(byte[], int, int, byte[], int)
*/
public int encrypt(byte[] input, int offset, int length, byte[] output,
int outOffset) throws ShortBufferException,
IllegalBlockSizeException, BadPaddingException {
return encrypter.doFinal(input, offset, length, output, outOffset);
}
/**
* @throws BadPaddingException
* @throws IllegalBlockSizeException
* @throws ShortBufferException
* @throws InvalidAlgorithmParameterException
* @throws InvalidKeyException
* @see memetic.crypto.Crypt#decrypt(byte[], int, int, byte[], int)
*/
public int decrypt(byte[] input, int offset, int length, byte[] output,
int outOffset) throws ShortBufferException,
IllegalBlockSizeException, BadPaddingException {
return decrypter.doFinal(input, offset, length, output, outOffset);
}
/**
* @see memetic.crypto.Crypt#getEncryptOutputSize(int)
*/
public int getEncryptOutputSize(int inputSize) {
return encrypter.getOutputSize(inputSize);
}
/**
* @see memetic.crypto.Crypt#getDecryptOutputSize(int)
*/
public int getDecryptOutputSize(int inputSize) {
return decrypter.getOutputSize(inputSize);
}
/**
* @see memetic.crypto.Crypt#getBlockSize()
*/
public int getBlockSize() {
return encrypter.getBlockSize();
}
}